The relationship between Gulf Stream (GS) transport and coastal sea level is investigated using monthly GS transport between 1993–2019 at Florida Straits and ten altimeter tracks. The results show that GS transport decorrelates quickly along its path, indicating it is misleading to assume that transport at a particular location represents strength of the GS as a whole. GS transport south of Cape Hatteras is significantly correlated with coastal sea level in both the South Atlantic Bight (SAB) and Middle Atlantic Bight (MAB). However, the significant correlations in MAB are due to their concurrent response wind on the shelf—the correlation becomes insignificant once the influence of local winds is removed. North of Cape Hatteras, the influence of GS transport on sea level is mostly over the deep ocean and rarely on the shelf, indicating that there is no dynamic link between the GS transport and coastal sea level in this region.

The Gulf Stream is expected to slow and shift poleward over the next century due to climate change. We investigate whether such changes are already observable in the altimetric record (1993–2018) using along-track altimetry. Trends in latitude, speed, transport, and width are calculated in stream-following coordinates to avoid aliasing possible increases in variability into changes in the Stream’s intrinsic structure. Statistically significant trends are few and apparently randomly distributed. Further, small changes to the length of the record lead to large changes in the trends and their significance. These results indicate that the probability there have been systematic change in the properties considered is low. Assuming that there may be physical reasons for the trends, we estimate that 22–23 additional years of observations are required detect trends in latitude and transport, and 54 additional years for trends in speed for at least half of the altimetry tracks.